Field of the Invention
The present invention relates to a detection apparatus which detects the position of a mark on a substrate, a lithography apparatus using it, a method of manufacturing an article, and a detection method.
Description of the Related Art
In a lithography apparatus, a detection unit (detection apparatus) which detects the position of a mark on a substrate is provided and the substrate is positioned based on a result of detection by the detection unit. For example, the detection unit includes an image sensor which captures an image of the mark on the substrate and detects the position of the mark using the image obtained by the image sensor. However, the mark on the substrate can have a different state (such as the reflectance of light, the shape, or the like) among, for example, a plurality of substrates (lots). Accordingly, the output value of the image sensor falls outside a target range depending on the state of the mark, making it difficult to detect the position of the mark accurately.
Japanese Patent Laid-Open No. 2004-219479 proposes a method of performing, before image capturing (actual image capturing) for detecting a position of a mark on a substrate, image capturing (photometry) for determining an image capturing condition of the actual image capturing. In Japanese Patent Laid-Open No. 2004-219479, photometric operations are performed a plurality of times on the different image capturing conditions of an image sensor, and the image capturing condition on which a photometric value falls within the effective dynamic range of the image sensor is determined as the image capturing condition in the actual image capturing.
In the method described in Japanese Patent Laid-Open No. 2004-219479, a time for performing each of the plurality of photometric operations is not defined. Thus, it may take a considerable time to perform the plurality of photometric operations. In this case, the start of the actual image capturing may be delayed from a desired timing, decreasing throughput.